Free online M2A to AU converter

Source format: M2A

M2A is an older MPEG-2 audio file format, usually containing compressed audio extracted from video or broadcast workflows. It was used in some digital video and DVD-related production environments, and you may still encounter it in archived media, editing projects, or legacy capture systems. In practice, M2A files are typically used when audio needs to be stored separately from video while keeping compatibility with MPEG-based tools.

Target format: AU

AU is a classic Sun/NeXT audio format that stores audio in a simple container, often with PCM or other basic codecs. It is widely recognized by older Unix systems and many audio utilities. AU is valued for its simplicity and broad support in technical and legacy environments, especially when a straightforward uncompressed or lightly compressed audio file is needed.

How to perform the conversion

The most reliable way to convert M2A to AU is with FFmpeg, because it supports both formats and gives you control over the output codec.

1. Install FFmpeg if it is not already available on your system.
2. Open a terminal or command prompt in the folder containing your M2A file.
3. Run a command such as ffmpeg -i input.m2a output.au.
4. If you want a specific audio codec for AU, you can force one, for example ffmpeg -i input.m2a -c:a pcm_s16be output.au.
5. Check the resulting AU file by opening it in an audio player or inspecting it with ffprobe output.au.

If you prefer a graphical workflow, some desktop audio editors and media tools can open M2A or import it through FFmpeg support, then export to AU using File → Export or File → Save as. If you want a quick browser-based option, you can convert the file on 101convert.com for free without installing any software.

Notes on quality and compatibility

M2A is already compressed audio, so converting it to AU does not improve quality. If the AU file is saved as uncompressed PCM, the file size will usually increase significantly. If the source M2A contains a codec that is not directly supported by the target AU container, FFmpeg will re-encode the audio during conversion.

Compatibility is generally good for basic AU playback, but some older players expect specific sample rates, channel layouts, or PCM endianness. For maximum compatibility, PCM AU is usually the safest choice. Also note that if the M2A file is part of a larger video workflow, it may contain only the audio stream, so make sure you are converting the correct track and not expecting video data to be preserved.